MENLO PARK, United States — Since 2003, when Web 2.0 first hit the mainstream, we’ve seen an explosion of user-generated content (UGC). Since then, fashion innovators have harnessed the growth of UGC to build experiences like Polyvore, where consumers can mix and match their favourite fashion items for others to see and shop. But as more and more consumers become increasingly active on the social web, the volume of content being